One way clutch

ABSTRACT

This invention is to provide a novel one-way clutch mechanism arranged characteristically such that a clutch ring so shaped as to be gradually increased in thickness from one side to the other is inserted between the inner and outer races through the media of sprag means inclined at a given angle relative to the axis of said inner and outer races, whereby the axial movements of said sprag means caused in conversion from and to the clutch action and the rolling action are all absorbed by said clutch ring.

United States Patent [1 1) Takata 1 Apr. 2, 1974 1 ONE WAY CLUTCH NobuoTakata, Osaka, Japan [73] Assignce: Toskin Seiki C0,, Ltd.

[22] Filed: Sept. 7, 1972 I21] Appl. No.: 287,097

[75] Inventor:

[30] Foreign Application Priority Data June 14, 1972 Japan 47-58620 [52]US. Cl. 192/45 [51] Int. Cl....., Fl6d 41/07 [58] Field of Search192/45; 188/8284 [56] References Cited 1 UNITED STATES PATENTS 1,834,84312/1931 Humfrey 192/45 1,670,197 5/1928 Humfrey.... 192/45 3,187,8636/1965 Cviometti 192/45 10/1968 l/l97l Auriol 192/45 Takada 192/45Primary Examiner-Allan D. Herrmann Attorney, Agent, or Firm-Hill,Sherman, Meroni, Gross & Simpson I 57] ABSTRACT This invention is toprovide a novel one-way clutch mechanism arranged characteristicallysuch that a clutch ring so shaped as to be gradually increased inthickness from one side to the other is inserted between the inner andouter races through the media of sprag means inclined at a given anglerelative to the axis of said inner and outer races, whereby the axialmovements of said sprag means caused in conversion from and to theclutch action and the rolling action are all absorbed by said clutchring.

5 Claims, 6 Drawing Figures PATENIEUAPR elm 1 3300.927

' sum 1 0f 2 ONE WAY CLUTCH The heretofore device one-way clutchesinclude the following two types: the type (type A) in which, in order tocheck relative rotation of the inner and outer races, a part of theperiphery of the cylindrical body of each sprag is deformed or a springis mounted on each sprag or otherwise the cylindrical clutching face ofthe inner or outer race deformed, so as to integrately join the innerand outer races by utilizing the frictional force combined with thewedging action offered by the sprags arranged in plurality between theinner and outer races, and the type (type B) in which the sprags andinner and outer races are arranged to form a plane of rotation of asuitable line when they are rotated about their axes, and the sprags arearranged with their axes inclined relative to the axes of the inner andouter races, so that when they are rotated in one direction, the spragswill attract the inner and outer races by the frictional force developedby said sprags to thereby integrate said both inner and outer races.

However, type A had the drawbacks that slippage takes place between thesprags and the clutching faces of the inner and outer races duringidling of the inner race to promote wear, that since the clutchingaction is effected impulsively, there is high possibility of causingdamage to the sprags and to the clutching faces of the inner and outer.races, that high machining accuracy is required for working of theperipheral faces of the sprags, for mounting of springs and formachining of the clutching faces of the inner and outer races so thatall the sprags may participate uniformly in developing the desiredclutching action, and that high precision bearings must be prepared tosustain load during idling and to ensure uniform clutching performancewhen the clutch is applied.

On the other hand, the type B clutches, although able to substantiallyovercome the defects of type A, depend on the axial drawing orattracting action of the sprags against the inner and outer races forintegrally uniting the latter. This necessarily requires a structurethat enables axial movement of the inner or outer race to be clutched. aI

Further, since the sprags and the clutching faces of the inner and outerraces, when assembled into a clutch, have respectively a certaincurvature of rotation relative to the axis, the inner and outer racesare made in sets. Moreover, a spline shaft or a sliding key must beprovided on the inner or outer race on cope with the axial drawingaction exerted to the outer race. Even if More specifically, there isprovided according to the present invention an improved one-way clutcharrangement in which a clutch ring so shaped as to be graduallyincreased in thickness from one side to the other is inserted betweenthe inner and outer races in such a way that the inner and outer sidesof said clutch ring will be contacted with said inner and outer racesthrough the media of sprags inclined at a given angle relative to theaxes of said inner and outer races, such that the axial movement of thesprags caused during the clutching and rolling actions will be absorbedby the movement of said clutch ring so as to lessen the shock or impactexperienced when the clutch is applied. The device of the presentinvention is also able to perform the role of roll bearing during idlingto markedly lessen wear of the inner and outer races as well as thesprags and eliminate any need of providing roll bearings which wereindispensable in the conventional type A clutches. The present devicecan also reduce the conventional defects concomitant to the axialmovement of the inner and outer races at the time of clutching and/orrolling action, so that there is no need of increasing the wallthickness of the inner and outer races as required in the type Bclutches.

FIG. 1 is a sectional view showing a clutch arrangement in an embodimentof the present invention;

FIG. 2 is a sectional view showing the configuration of a clutch ringused in the assembly of FIG. 1;

FIG. 3 is a perspective view, partly shown in section, illustrating themodes of operation of the respective component members;

FIG. 4 is front views of various types of sprags usable in the presentinvention;

FIG. 5 is a perspective view illustrating a manner of use of a sprag incase double ball-ended sprags were used in the present invention, and asectional view showing the sprag guide grooves; and

FIG. 6 is perspective views of sprag cages.

Any type of sprags available can be used in the present invention,provided that they have a rollable curved' such spline shaft or slidingkey is provided, expansion and contraction take place inevitably in theouter and the inner races, respectively, since the former receives alarge internal pressure and the latter a large external pressure whenthe clutch is applied. Should expansion or contraction take place on theside where the spline shaft or sliding'key is provided, an interferencefit situation may be developed to hinder the axial movement of theraces, so that a sufficient wall thickness to get rid of suchpossibility is required. This naturally necessitates increased amount ofmaterial and space, resulting in a large-sized clutch for a certainprescribed amount of torque.

The present invention has been deviced with the object of sweeping awayall of these defects of both type A and type B clutches which have beenavailable heretofore.

surface centered by the axis, but it is usually preferred to useconvergent-divergent rollable bodies for the inner sprags and barrelshaped ones for the outer sprags, with a suitable inclination beinggiven to each of these sprags, or the double ball-ended type for bothinner and outer sprags. In this case, the clutching face of each of theinner and outer races may be cylindrical or conical, with the busthereof being rectilinear. Therefore, if the clutch engaging medium iscomposed of a cylindrical or conical shaft and cylindrical or conicalhole combination, there is no need of preparing specific inner and outerraces. It is therefore possible, by combining the inner and outersprags, inner and outer sprag cages, clutch ring and clutch thrustbearing in one set, to greatly facilitate the assembling of the clutchand to realize marked economization in manufacture of the clutches.

The one-way clutch of the present invention is now described in furtherdetail by way of an embodiment thereof where an inner race having acylindrical shaft and an outer race having a cylindrical hole are usedas shown in FIG. 1. The assembly of FIG. 1 comprises an outer race 1having a cylindrical hole, an inner race 2 having a cylindrical shaft,an outer sprag cage 3, an inner sprag cage 4, a clutch ring 5 providedwith guide flanges 6 and 7 adapted to serve as roll bearing during freerotation, a clutch ring thrust bearing 8, outer sprags 9 and innersprags 10.

The principles in operation and arrangement of these component parts areas follows:

1. The outer and inner peripheral sprags 9 and 10 are inclined in thesame direction relative to the axes of the clutching faces of the outerand inner races 1 and 2 in concordance with the given clutchingdirection;

2. Sprags must be contacted at more than two locations on the clutchingfaces of the outer and inner races 1, 2 and clutch ring to ensurestabilized inclination at all times;

3. The sprags 9, 10 may be of any desired shape provided that it has arolling face of a certain segment about the axis, but selection of theshape must be made by taking into account the rolling action, torquecapacity of the clutch, workability, pattern of use, and other likefactors.

4. The clutch ring 5 must have a conoidal configuration with itsthickness beingv increased'from one side to the other. Otherwise, nodrawing action at the time of clutching nor rolling action during freerotation will be provided.

5. Sprag cages 3, 4.are designed to be servable as roll bearing and toalsoprepare guide flanges 6, 7 and thrust bearing 8 designed to ensureprevention of accidental removal of the'sprags and smooth rotation ofthe clutch ring. 1 g

If these five principles are observed, the desired oneway clutchfunction will be provided.

Now, the clutching and rolling actions brought about by theabove-described arrangement of the component parts are discussed.

Referring to FIG. 3, let it be assumed that the sprags 9 and 10 arefitted in position iwth inclinations of a and B, respectively, and thatthe clutch ring 5 is formed conically with its thickness enlargedupwardly in the drawing. Under this condition, if the clutch ring 5 isrotated in the direction of arrow A, the sprags 9 and 10 are caused torotate in the directions of arrows B and C, respectively, so that theyare rolled down toward the thinner side of the clutch ring 5. If thissituation is examined from the angle of the inner and outer races 2 andl, the clutch ring 5 is forced out upwardly in the direction wherespaces are created, and is therefore caused to roll in a substantiallyno-load condition. If the clutch ring 5 is rotated in the direction ofarrow A, the inner and outer sprags 10 and 9 act to drag in the clutchring 5 downwardly as far as no axial slippage is caused on the inner andouter sprags l0 and 9. In this case, since the clutch ring 5 is soshaped that its thickness is gradually increased toward its top part,there is produced a situation as if a wedge has been driven in betweenthe inner and outer peripheral sprags l0 and 9, and hence the entirecomponent combined, that is, clutched.

As will be appreciated from the foregoing explanation, both rolling andclutching actions exert no influence to the inner and outer races 1 and2 and is effected merely by axial rolling movement of the inner andouter peripheral sprags relative to the clutch ring.

In the foregoing discussion, the behavior of the clutch ring 5 wasdiscussed to explain the rolling and clutching actions for simplifyingthe explanation, but in practical uses, the outer race 1 or the inner,race 2 is roparts are integrally tated to give rotation to eitherof theinner peripheral sprag 10 or the outer peripheral sprag 9, causingcorresponding rotation of the clutch ring 5 and other sprags 9 or 10, sothat the same actions as described above are produced.

As for the configurations of the sprags 9 and 10 used, it is possible touse any configurations if they have a rolling face of a certain segmentabout the axis as mentioned before, but actually, it is usuallypreferred to use the rolling bodies such as employed in roll bearing. InFIG. 4 are shown some typical examples of preferred rollerconfigurations, (a) showing a double ball ended roller, (b) acylindrical roller, (0) a conoidal roller, (d) a barrel shaped roller,and (e) a convergent-divergent roller. These rollers can be used incombination as inner and outer peripheral sprags, and selection ofeither of these rollers determines by itself the configurations of theinner and outer races as well as the clutching faces of the clutch ringto be used. It can also decide whether the inner and outer races must beprepared in set or such races can be dispensed with.

I-Iere, the matters to be observed in use of either of these rollers arebriefly described. In case of using the double ball-ended rollers (a),the ball grooves must be I provided on the clutching face at a pitchsmaller by the amount of roller inclination that the distance betweenthe cores of the two balls to thereby stabilize the inclination (seeFIG. 5). In the case of (b) and (c), both the inner and outer peripheralfaces of the clutch ring must be formed into hyperboloid of one sheetcorresponding to the amount of inclination of the sprags. Naturally, theinner and outer races 1 and 2 must be manufactured in set. Otherwise,every counterpart shaft and counterpart housing must be also worked intohyperboloid of one sheet. In the case of (d), if this is used on theinner peripheral face, the inner peripheral face may be cylindrical orconical face, and in the case of (e), if this is used on the outerperipheral face, the outer peripheral face may be cylindrical or conicalface. But, if they are used reversed, a corresponding hyperboloid of onesheet must be provided. Therefore, when utilizing the cylindrical faceon the counterpart shaft and cylindrical hole in the counterparthousing, the arrangement may be such as shown in FIG. 1, using barrelshaped rollers (d) for the outer peripheral sprags 9 andconvergent-divergent rollers (e) for the inner peripheral sprags 10. Inthis case, both inner and outer surfaces of the clutchring take theshape of hyperboloid of one sheet as shown in FIG. 2.

When this one-way clutch works as roll bearing, the inner and outerperipheral sprags are rolled out toward the thinner side of the clutchring, so that it needs to provide means for stopping and guiding them.To this end, guide flanges such as shown by numerals 6 and 7 in FIG. 1are provided. Although such guide flanges can prevent dislocation orremoval of the sprags, they are not sufficient to check the entireassembly of clutch ring 5 and sprags 9, 10 from coming out in theopposite direction, so it is desirable to provide a clutch ring thrustbearing such as illustrated in FIG. 1 with numeral 8.

According to the present invention, as described above, any axialmovement of the sprags during the clutching performance is absorbed bythe clutch ring, so that the inner and outer races 1 and 2 remainperfectly unaffected by the clutching action and also the structure ofthe device can be made small and simple tained an excellent one-wayclutch which is easy to assemble and handle, low in cost and high indurability.

What is claimed is: I

l. A one-way clutch comprising an inner race, an outer race having aninner surface parallel to the axial direction thereof, a conoidalframe-like clutch ring shaped so as to increase in thickness from oneside to the other relative to the axial direction of said inner andouter races and mounted between said inner and outer races, a pluralityof sprags inclined at a certain predetermined angle relative to theaxial direction of said inner and outer races and mounted between saidinner and outer races and said clutch ring, so that any relativerotational movement of said inner and outer races in a first directioncauses rolling action and rotation in the opposite direction causeslocking action which is absorbed by said clutch ring.

2. A one-way clutch according to claim 1, in which guide flanges areprovided on the reduced thickness side of said clutch ring and a thrustbearing mounted adjacent the thick side of said clutch ring.

3. A one-way clutch as defined in claim 1 including a pair of spragcages in which said sprags are supported.

4. A one-way clutch according to claim 1, in which said clutch ring isformed into a conoidal frame-like structure.

5. A one-way clutch according to claim 1, wherein said sprags aredouble-ball ended rollers having different sizes.

1. A one-way clutch comprising an inner race, an outer race having aninner surface parallel to the axial direction thereof, a conoidalframe-like clutch ring shaped so as to increase in thickness from oneside to the other relative to the axial direction of said inner andouter races and mounted between said inner and outer races, a pluralityof sprags inclined at a certain predetermined angle relative to theaxial direction of said inner and outer races and mounted between saidinner and outer races and said clutch ring, so that any relativerotational movement of said inner and outer races in a first directioncauses rolling action and rotation in the opposite direction causeslocking action which is absorbed by said clutch ring.
 2. A one-wayclutch according to claim 1, in which guide flanges are provided on thereduced thickness side of said clutch ring and a thrust bearing mountedadjacent the thick side of said clutch ring.
 3. A one-way clutch asdefined in claim 1 including a pair of sprag cages in which said spragsare suppoRted.
 4. A one-way clutch according to claim 1, in which saidclutch ring is formed into a conoidal frame-like structure.
 5. A one-wayclutch according to claim 1, wherein said sprags are double-ball endedrollers having different sizes.